Amperometric sensing of ethylene oxide in the gas phase.

The sensing device used is based on a porous Pt electrode, which is supported on an ion-exchange membrane and directly exposed to the gas phase. Under acid conditions, ethylene oxide was found to be oxidized on the platinum oxide surface at +550 mV vs MSE, thus enabling its monitoring via the measurement of the associated current. A detection limit of 15 ppb was obtained, based on a signal-to-noise ratio of three, and a linear dynamic range was found up to 100 ppm. The effects of mass transport, humidity, and oxygen on the cell response, as well as the cross sensitivity to other organic vapors and inorganic gases are discussed.

Nature of Candida albicans-derived carbohydrate antigen recognized by a monoclonal antibody in patient sera and distribution over Candida species.

The minimal epitope of an anti-Candida albicans mannan monoclonal antibody (MAb) EB-CA1, used to detect mannanemia in patient sera, was determined, MAb EB-CA1 exhibited reactivity with oligomannosides released from the mannan acid stable domain, converted into neoglycolipids (NGLs) and coated onto ELISA plates. Reactivity occurred with mannopentaose and higher oligomers, whereas mannotriose and mannotetraose were unreactive. MAb EB-CA1 binding to mannan acid stable mannopentaose NGL displayed a dose dependent and saturable specific reactivity curve whereas there was a complete absence of binding, even at high concentrations, with NGLs constructed from the beta-1,2-linked mannopentaose derived from the mannan acid labile fraction. MAb EB-CA1 binding to acid stable mannopentaose NGL was inhibited by the homologous oligomannoside but not by mannotriose and mannotetraose. NMR analysis showed that mannotriose and mannotetraose contained exclusively alpha-1,2-linked D-mannopyranose units and that mannopentaose was a mixture of a mannopentaose alpha-1,2-linked and an isomer in which the fifth mannose was alpha-1,6-linked to the reducing unit of manno-alpha-1,2 tetraose. Western blot analysis has shown that MAb EB-CA1 epitope was expressed on a wide range of C. albicans manno-glycoconjugate as well as on manno-glycoconjugates of other pathogenic species of the genus Candida, viz. C. tropicalis, C. glabrata, C. parapsilosis and C. krusei.

Specific antibody response to oligomannosidic epitopes in Crohn's disease.

Elevated antibody levels against the yeast Saccharomyces cerevisiae have been reported in sera from patients with Crohn's disease and not with ulcerative colitis. The aim of the study was to identify the nature of the epitopes supporting this antibody response. Whole cells from different S. cerevisiae strains were selected in immunofluorescence assay for their ability to differentiate the antibody responses of patients with Crohn's disease and ulcerative colitis. Their cell wall phosphopeptidomannans were then tested as antigen in enzyme-linked immunosorbent assay (ELISA) against sera from 42 patients with Crohn's disease, 20 patients with ulcerative colitis, and 34 healthy controls. Graded chemical degradations were performed on the most reactive strain phosphopeptidomannan. The discriminating epitope was determined through gas-liquid chromatography-mass spectrometry. The greatest discrimination among patients with Crohn's disease, ulcerative colitis, and controls was obtained with Su1, a S. cerevisiae strain used in brewing of beer. ELISA directed against phosphopeptidomannan of this strain was 64% sensitive and 77% specific for discriminating Crohn's disease versus ulcerative colitis and 71% sensitive and 89% specific for Crohn's disease versus controls. Periodate oxidation and selective degradation demonstrated that the most important polysaccharide epitope was shared by both the acid-stable and the alkali-labile domains of the phosphopeptidomannan. The determination of oligomannose sequences of S. cerevisiae Su1 phosphopeptidomannans suggested that a mannotetraose, Man (1 --> 3)Man(1 --> 2)Man(1 --> 2)Man, supported the serological response seen in Crohn's disease. Further identification of the immunogen eliciting this antibody response as a marker of the disease may help to understand its etiology.

Change in glycosylation of chicken transferrin glycans biosynthesized during embryogenesis and primary culture of embryo hepatocytes.

Transferrins were isolated by immunoaffinity chromatography from chicken serum, chicken embryo serum and from the culture medium of chicken embryo hepatocytes in primary culture. The glycovariants of these three transferrins were separated by ion-exchange chromatography using a fast protein liquid chromatography (FPLC) system. The structures of the oligosaccharide-alditols released by hydrazinolysis from the glycovariants were compared after analysis by a combination of methanolysis, methylation analysis and 1H-NMR spectroscopy. In the three transferrins analysed, the oligosaccharides were of the biantennary N-acetyllactosaminic type, having several prominent features. In particular, the embryo serum transferrin glycan differed from that of chicken serum transferrin by the presence of a bisecting N-acetylglucosamine, suggesting a developmental change in glycosylation. The glycan structure of the transferrin secreted by the embryo hepatocytes in primary culture was marked by the presence of fucose (alpha 1-6) linked to the core N-acetylglucosamine, suggesting that expression of the fucosyltransferase activity is dependent on cell culture conditions. Moreover, comparative analysis of chicken serum transferrin and ovotransferrin glycans reinforces the idea that the glycosylation of two identical polypeptide chains is organ specific.

Probable presence of beta(1-2)-linked oligomannosides that act as human immunoglobulin G3 epitopes and are distributed over a Candida albicans 14- to 18-kilodalton antigen.

Kinetic analysis of candidosis patients' immunoglobulin G3 response has shown that reactivity towards beta(1-2)-linked mannan-derived oligomannosides was associated with the recognition through metaperiodate-sensitive epitopes of a 14- to 18-kDa Candida albicans antigen unreactive with concanavalin A.

Mapping of Candida albicans oligomannosidic epitopes by using monoclonal antibodies.

Six monoclonal antibodies (MAbs) from various laboratory sources (EB-CA1, EB-CA2, H5, AF1, C6, and 5B2), reacting with the polysaccharidic moieties of Candida albicans mannoproteins, were used for epitope mapping by an enzyme-linked immunosorbent assay (ELISA) with neoglycolipids and by Western blotting (immunoblotting) of a C. albicans germ tube extract. The ELISA involved neoglycolipids constructed from three families of oligomannosides released by sequential depolymerization of C. albicans phosphopeptidomannan by acid hydrolysis (NGLH), beta-elimination (NGLO), and acetolysis (NGLA). All of the MAbs exhibited low reactivities against NGLO. MAbs EB-CA1, EB-CA2, and H5 reacted mainly against NGLA, and MAbs C6 and AF1 recognized mainly NGLH, whereas MAb 5B2 reacted with both families of neoantigens. When this method was compared with Western blotting, strong reactivity to NGLA was associated with the presence of epitopes shared by high-molecular-weight mannoproteins, whereas strong reactivity to NGLH was associated with a reactivity to a family of 14- to 18-kDa antigens. The reactivity of MAb 5B2 was associated with both high-molecular-weight mannoproteins and the 14- to 18-kDa antigens. In relation to the present knowledge about the structure of the C. albicans phosphopeptidomannan oligomannosidic repertoire, these results provide preliminary data concerning the molecular basis of the recognition of mannopyranosyl sequences by MAbs and their distribution among C. albicans mannoproteins.

[Alkalization of bupivacaine in the combination fentanyl-bupivacaine in epidural obstetrical analgesia]. / Alcalinisation de la bupivacaïne dans l'association fentanyl-bupivacaïne pour l'analgésie péridurale obstétricale.

A randomized double blind study was carried out to determine whether alkalization of a 0.25% bupivacaine solution in a fentanyl-bupivacaine mixture hastened the onset, and increased the duration and quality, of extradural analgesia during labour. The study included 120 women with uncomplicated full-term gestation. Prior to the extradural injection, 0.1 ml of either 8.4% sodium bicarbonate or normal saline was randomly added to 20 ml of 0.25% bupivacaine. The patients were given 75 micrograms fentanyl with 12 ml of either alkalized or unaltered bupivacaine. Data for analysis were obtained in 106 parturients (bicarbonate group n = 54; control group n = 52). The pH of alkalized and unaltered bupivacaine were 7.07 +/- 0.01 and 5.56 +/- 0.01 respectively. There were no statistically significant differences between the bicarbonate and control groups with regard to the speed of onset of analgesia (7.08 +/- 0.7 min vs. 6.78 +/- 0.6 min), its duration (123.6 +/- 10.7 min vs. 113 +/- 6.6 min), and the number of cases of inadequate pain relief (6 and 3 respectively). The rate of maternal adverse effects, and neonatal status, were similar in both groups. It can be concluded that alkalizing a 0.25% bupivacaine solution in a fentanyl-bupivacaine mixture for epidural analgesia in labour has no clinical value.

Intravenous propofol during cesarean section: placental transfer, concentrations in breast milk, and neonatal effects. A preliminary study.

Placental transfer and neonatal effects of propofol were investigated in 21 women undergoing elective cesarean section under general anesthesia. This study was conducted in two separate phases according to the use of propofol. In both phases, anesthesia was induced with an iv bolus of 2.5 mg/kg of propofol. In phase 1 (n = 10), anesthesia was maintained with 50% nitrous oxide in oxygen and halothane. In phase 2 (n = 11), a continuous infusion of propofol at a rate of 5 mg.kg-1.h-1 was started after the induction dose. Maternal venous and umbilical cord arterial and venous samples were obtained at delivery. The propofol concentration in whole blood was measured with a high performance liquid chromatography method. Where possible, breast milk/colostrum was expressed for both phases postoperatively and a sample of blood was collected during phase 2 from neonates via a heel prick 2 h after birth. Propofol crossed the placenta, as demonstrated by concentrations found in umbilical venous blood in phase 1 (0.13-0.75 micrograms/ml) and in phase 2 (0.78-1.37 micrograms/ml). At delivery, the ratio of the drug concentration in umbilical venous blood to that in maternal blood was 0.70 +/- 0.06 for phase 1 and 0.76 +/- 0.10 for phase 2. The ratio of propofol concentration in the umbilical artery to that in the umbilical vein was 1.09 +/- 0.04 for phase 1 and 0.70 +/- 0.05 for phase 2.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of diluting fentanyl on epidural bupivacaine during labor analgesia.

In a randomized prospective study carried out on 60 laboring primiparous parturients, fentanyl 80 micrograms, either in 2 ml or in 8 ml, was added to 12 ml of 0.25% bupivacaine administered epidurally for pain relief. The aims of this protocol were to evaluate the effect of varying the volume of fentanyl added to epidural bupivacaine on the quality and duration of labor analgesia. There was no significant difference in either the duration or quality of analgesia between the two groups. The incidence of pruritus was higher in the fentanyl-diluted group (43% versus 23%). No clinical advantage was found in this study, therefore, when fentanyl 80 micrograms was added to 0.25% bupivacaine.

[Neonatal effects of propofol administered to the mother in anesthesia in cesarean section]. / Effets néonatals du propofol administré à la mère pour l'anesthésie de la césarienne.

Propofol, 2-6 diisopropylphenol ("Diprivan", ICI) has been shown to be safe and effective for induction and maintenance of anesthesia when injected intravenously. Its pharmacological profile suggests that it may prove to be a useful agent in obstetric anesthetic practice. But, obstetrics is a specialized field in which the acute effects of the anesthetic agent on the fetus must be considered. This open non comparative study was therefore designed to investigate the neonatal assessments when propofol was used either for induction of anesthesia or for induction and maintenance of anesthesia during elective cesarean section. This study was conducted in two separate phases according to the use of propofol. In both phases, anesthesia was induced with an intravenous bolus of 2.5 mg.kg-1 of propofol. In phase 1 (n = 10), anesthesia was maintained with 50% nitrous oxide in oxygen and halothane. In phase 2 (n = 11), a continuous infusion of propofol at a rate of 5 mg.kg-1.h-1 was started after the induction dose. At time of delivery, blood samples were taken from maternal artery, umbilical vein and artery for acid-base and blood gas status. The condition of the infant was evaluated using Apgar score at 1, 5 and 10 min, time to sustained spontaneous respiration and the Neurologic and Adaptative Capacity Score was assessed at 30 min, 2 hours and 24 hours after birth. Maternal and neonatal blood gas tensions and acid-base status at delivery were within the normal clinical limits in both phases and compared favorably with results published by others workers using established methods of anesthesia.(ABSTRACT TRUNCATED AT 250 WORDS)

Controlled trial of extradural bupivacaine with fentanyl, morphine or placebo for pain relief in labour.

In a prospective, randomized double-blind study carried out on 255 parturients, fentanyl 80 micrograms (n = 81), morphine 4 mg (n = 83) or placebo (n = 85) was added to 0.25% bupivacaine administered extradurally for pain relief during labour. Fentanyl increased the mean duration of bupivacaine analgesia by 30% and did not reduce the rate of inadequate pain relief. Morphine did not increase the mean duration of bupivacaine analgesia significantly, but increased the rate of inadequate pain relief. It was concluded that morphine 4 mg added to extradural 0.25% bupivacaine was of no value.

[A combination of sufentanil and 0.25% bupivacaine administered epidurally for obstetrical analgesia. Comparison with fentanyl and placebo]. / Association sufentanil-bupivacaïne à 0.25% par voie péridurale pour l'analgésie obstétricale. Comparaison avec le fentanyl et un placebo.

The study reported was designed to determine whether 15 micrograms sufentanil would provide analgesia comparable in duration and quality with that given by 75 micrograms fentanyl, when associated with plain 0.25% bupivacaine for extradural analgesia for labour. Patients (n = 124) in labour and at full term were randomly divided into 3 groups. Group 1 (n = 41) were given 12 ml of 0.25% plain bupivacaine with saline, group 2 (n = 41) 12 ml of 0.25% plain bupivacaine with 75 micrograms fentanyl and group 3 (n = 42) 12 ml of 0.25% plain bupivacaine with 15 micrograms sufentanil. 11 cases were excluded from the study (8 Caesarean sections, 3 technical failures). The duration of analgesia obtained with the two opioids was similar (group 2: 126.7 +/- 6.5 min, p less than 0.01; group 3: 114.9 +/- 5.8 min, p less than 0.01; group 1: 93.6 +/- 5.4 min) as well as the quality of pain relief. There were no differences between the three groups with regard to Apgar scores. The only side-effect seen with sufentanil and fentanyl was pruritus (group 2: 21.9%, p less than 0.05; group 3: 21.4%, p less than 0.05; group 1: 2.4%). These results showed that 15 micrograms sufentanil could replace 75 micrograms fentanyl for extradural pain relief of labour with plain 0.25% bupivacaine. However, the use of opioids with local anaesthetics would seem to be of interest only if labour is likely to be prolonged.

[Peroperative anaphylactic shock caused by latex]. / Choc anaphylactique peropératoire au latex.

A case is reported of severe anaphylactic shock occurring in a 32 yr old woman after foetal extraction during caesarean section. The agent responsible was the latex from the surgical gloves used. This was proved by the different allergological tests carried out: positive prick-tests to the latex, positive human basophil degranulation test and the finding of specific anti-latex IgE. All the tests carried out using the anaesthetic drugs were negative.